Is a RCD neccessary for a 10.5kw shower

[daveg4]

Replacing a 7kw shower with a 10.5kw.
I think the cable is a 6mm so replacing with a 10mm. The original was the three red, black and green loose in a conduit from the consumer unit to twin pole isolator to shower 8 meter run.
The consumer unit is a Hager which was fitted with a 32A breaker for the shower. I have replaced that with a 50A as was told that a 45A was not available but 50 was OK. There is no RCD in the consumer unit so am thinking about putting one in the circuit on exit from consumer unit.
tlc.direct have such RCD's in their own box for such installations, guessing I will need the 63amp as 40amp to weak.
Summing up, new 50 amp breaker, 63 amp RCD protector in circuit, 10mm wire, (8m run), 45amp twin pole isolator switch.
I am capable of the installation, just want confirmation rating are correct.
Any help appreciated
Dave

 

[Spark123]

Under the 17th edition of the wiring regulations, all circuits in a bathroom need to be RCD protected with a 30mA max device.
The current carrying capacity of your run depends on how it is installed. The current carrying capacity of the cable should be larger than that of the protective device, i.e. greater than 50A.
The double poled isolator should also be 50A minimum.
This work is notifiable to your LABC under part p of the building regs.

 

[securespark]

Is the consumer unit just carrying the circuit for the shower?

If so, you could replace the main switch with an RCD.

If not, what rating is the main switch of this unit?

 

[daveg4]

Under the 17th edition of the wiring regulations, all circuits in a bathroom need to be RCD protected with a 30mA max device.
The current carrying capacity of your run depends on how it is installed. The current carrying capacity of the cable should be larger than that of the protective device, i.e. greater than 50A.
The double poled isolator should also be 50A minimum.
This work is notifiable to your LABC under part p of the building regs.

Thanks Spark123.
I have also noticed that the calculator says that i should use 16mm but the 10mm is rated for 53. Should i use 16mm cable?

 

[daveg4]

Under the 17th edition of the wiring regulations, all circuits in a bathroom need to be RCD protected with a 30mA max device.
The current carrying capacity of your run depends on how it is installed. The current carrying capacity of the cable should be larger than that of the protective device, i.e. greater than 50A.
The double poled isolator should also be 50A minimum.
This work is notifiable to your LABC under part p of the building regs.

Thanks Spark123.
I have also noticed that the calculator says that i should use 16mm but the 10mm is rated for 53. Should i use 16mm cable?

The cable is run in pvc conduit, loose under floor boards and in capping on outside bathroom wall.

 

[RF Lighting]

The consumer unit is a Hager which was fitted with a 32A breaker for the shower. I have replaced that with a 50A as was told that a 45A was not available but 50 was OK. There is no RCD in the consumer unit so am thinking about putting one in the circuit on exit from consumer unit.
tlc.direct have such RCD's in their own box for such installations, guessing I will need the 63amp as 40amp to weak.

Why not just install a 45A hager RCBO???

Hager part number AD127 (Single pole, 45A, 30mA, 6kA)

 

[daveg4]

Is the consumer unit just carrying the circuit for the shower?

If so, you could replace the main switch with an RCD.

If not, what rating is the main switch of this unit?

The rcd is in its own box in the shower line from the consumer unit via a 50a breaker and a 100a main breaker

 

[GaryMo]

Are you installing 10mm twin & earth or utilising the existing conduit with new 10mm single cables?
If it's twin & earth (which I'm assuming), will this pass through any conduit, trunking or thermal insulation?

 

[daveg4]

The consumer unit is a Hager which was fitted with a 32A breaker for the shower. I have replaced that with a 50A as was told that a 45A was not available but 50 was OK. There is no RCD in the consumer unit so am thinking about putting one in the circuit on exit from consumer unit.
tlc.direct have such RCD's in their own box for such installations, guessing I will need the 63amp as 40amp to weak.

Why not just install a 45A hager RCBO???

Hager part number AD127 (Single pole, 45A, 30mA, 6kA)

Thanks, will look into that tomorrow, thinking i may get an electrician in.

 

[securespark]

What size is the conduit?

 

[daveg4]

What size is the conduit?

20mm diam

 

[Taylortwocities]

You'll not never, nohow get 2x10mm + earth in 20mm conduit.

Also remember that not more than 45% of the space within the conduit or trunking can be occupied by cables.

You'll need to derate the cables too. Better to use twin&earth.

 

[GaryMo]

What size is the conduit?

20mm diam

Again,

Are you installing 10mm twin & earth or utilising the existing conduit with new 10mm single cables?
If it's twin & earth (which I'm assuming), will this pass through any conduit, trunking or thermal insulation?

10mm T&E carries 64A in perfect conditions.....

 

[Taylortwocities]

You'll not never, nohow get 2x10mm + earth in 20mm conduit.

.

You wont get singles in there, either.

 

[ban-all-sheds]

I have also noticed that the calculator says that i should use 16mm but the 10mm is rated for 53.

Which calculator is that?